A cleaning apparatus of this type includes a manipulator mounted on a carriage and carrying spray heads connected to a source of high pressure cleaning fluid. German Patent Publication (DE) 3,530,100 (Koehler) describes such an apparatus in which the spraying device is supported on a gantry-type carrier or on a robot capable of directing or aiming the spraying device onto the surface area to be cleaned. Rotating nozzles of the known spraying device are supplied with a high pressure liquid, especially water pressurized within the range of 400 to 700 bar, whereby the spraying device is able to achieve a high surface area coverage even if the spacing between the spray head and the surface area to be cleaned is within the range of up to 1.5 m. Cleaning operations performed at such pressures are suitable only for relatively thick-walled structural components, such as ships and the like. Components having relatively thin walls, such as commercial aircraft, buses, or passenger vehicles, could be damaged when it is necessary to remove lacquer coatings from the surface with a high pressurized liquid when the spacings between the nozzles and the surface cannot be properly controlled. Even if no damage should occur, an incomplete coating removal and cleaning may occur if surface area portions are not uniformly treated.